Certain gas turbine engines, such as aircraft gas turbine engines, include one or more rotating shafts that support compression and turbine aerodynamic turbomachinery. The one or more shafts require bearings to support thrust loads and radial loads imposed during operation. The bearings are housed in enclosures generally referred to as sumps. Gas turbine engines typically have a forward sump, a mid sump, and an aft sump. Additionally, certain gas turbine engines will contain an accessory drive gearbox with numerous gear meshes and shafts requiring supporting bearings. The shaft and gearbox bearings and gear meshes require continuous lubrication during operation. Additionally, lubrication must be scavenged from each of the lubrication sites and pumped back to a lubrication reservoir/oil tank for reuse.
A pumping element is typically included to provide lubrication to the various bearings and gear meshes, as well as to scavenge the lubrication from the respective sumps. Failure of the pumping element can result in termination of lubrication flow to all critical locations and failure of a scavenge element can result in flooding of the affected site. Flooding of the affected site can, in turn, result in depletion of lubrication in the reservoir and subsequent bearing failure and seizure. Such a failure may be of a particular safety concern in, for example, single engine aircraft applications.
Accordingly, a more robust pump would be beneficial. More particularly, a pump for a gas turbine engine having one or more redundant features such that the pump may continue operating subsequent to a failure would be particularly useful.